Year	Percent
1990	81.869
1991	81.659
1992	81.316
1993	81.18
1994	81.283
1995	81.524
1996	81.724
1997	81.596
1998	81.525
1999	81.532
2000	81.605
2001	81.644
2002	81.72
2003	81.805
2004	81.872
2005	81.906
2006	82.09
2007	82.183
2008	82.203
2009	82.158
2010	82.052
2011	82.745
2012	83.173
2013	82.517
2014	81.784
2015	80.949
2016	81.138
2017	81.25
2018	81.371
2019	81.507
2020	81.656
2021	81.769
2022	81.896
2023	82.019
2024	82.12
2025	82.184
2026	82.185
2027	82.159
2028	82.113
2029	82.055
2030	81.989